Haematology, Coagulation & Biochemistry sample advice

Complete blood counts (CBC)

Please submit:

  1. Two air-dried, unstained blood smears (with a feather edge that finishes between 50-75% the length of the slide) – please see the sampling protocols section of this website for how to make blood smears and also for handy tips / pitfalls to avoid
  2. Blood in EDTA (mixed well and filled to the fill-line)

Direct Coombs’ test

Please submit: blood in EDTA (mixed well and filled to the fill-line)

Coagulation tests (PT, aPTT)

Please submit:

Blood in sodium citrate (it is important that the ratio of sodium citrate to blood be 1:9 – hence please fill the tube to its fill line and please mix it well to prevent clotting). In our experience, PT and aPTT are stable for the normally expected transit time of 24-48 hours to the lab and do not require packaging on ice. Please also check the expiry dates on your sodium citrate tubes before using them.

Urine protein/creatinine ratio (UPC)

Please submit urine in a plain tube

Blood Biochemistry

Please submit: separated serum or spun/separated serum gel tube

In vitro sample haemolysis can affect the analysis of some biochemistry parameters (e.g. potassium) and therefore we recommend that blood samples be separated prior to submission. Allow the blood time to clot (30 mins) before centrifugation/separation.